In Japanese Patent Publication Number 2004-52988, a conventional pump device including a case, a pump in the case, a drive shaft inserted in the case, and a bearing for supporting the drive shaft so that drive shaft can freely rotate. The conventional pump device draws in and discharges fluid by driving the pump by using the drive shaft.
The conventional pump device uses, as the bearing for supporting the drive shaft, a needle bearing which lacks an inner race and therefore cannot restrict movement of the drive shaft relative to the bearing. As a consequence, it is difficult to prevent the drive shaft from escaping by means of the bearing. In order to prevent the drive shaft from escaping, an end of the drive shaft is inserted into a ring-like member and the other end of the drive shaft is radially enlarged. Therefore, an additional member (the ring-like member) is required in order to prevent the drive shaft from escaping. In this case the drive shaft has to be sufficiently extended so as to accommodate the ring-like member.